gistfile1.rs

trait Monoid {
 fn zero() -> Self;
 fn append(this: Self, that: Self) -> Self;
}

impl Monoid for int {
  fn zero() -> int { 0 }
  fn append (this: int, that: int) -> int { this + that }
}

fn fold<T : Monoid> (slice: &[T]) -> T {
  return slice.iter().fold(T::zero(), |acc, v| T::append(acc, v));
}


fn main() {
let xs: [int, ..5] = [1, 2, 3, 4, 5];

println!("{}", fold(xs));
}